Finely grate the ginger (1" cube), garlic (4 cloves) and lime zest (½ a lime). Finely chop the green chilli (½ chilli) and put it into a medium-sized bowl.
Add the other marinade ingredients (½ tsp hot chilli powder, 2 tsp ground coriander, 2 tsp ground cumin, ½ tsp fenugreek, 4 tbsp natural yogurt, salt) and mix everything together until everything is combined.
Trim off any excess fat from the lamb steaks and chop them into bite-sized cubes and add to the bowl. Mix together until the lamb is coated in the yogurt marinade.
Cover the bowl and refrigerate for about an hour.
Once the lamb has marinated, thread it onto the skewers.
Cook on a hot BBQ, in a pan, or under a grill for a couple of minutes on each side (for medium lamb, leave for 3 minutes on each side for well done).
Serve - Mine are served in homemade naan pittas with fresh spinach leaves, barbecued peppers and onions and drizzled with a little extra yogurt.